The relationship between fluctuation in the basking sharks, Cetorhinus Maximus (Gunnerus) population in Cornish coastal waters (SW England) and abiotic and biotic factors and the effect imposed by the North Atlantic Oscillation

This study reports on the abiotic and biotic factors which influence the basking sharks distributional patterns. A relationship was found between basking shark abundances and C. Helgolandicus abundances. Only a correlation was found between basking sharks and total copepods. This suggest that basking sharks are influenced by an individual species rather that the total abundance of copepods. Fluctuations in the distribution of C. Helgolandicus, where found to be associated with the North Atlantic Oscillation. It was suggested that C. Helgolandicus migrates into northern regions during a high NAO. This was suggested as being the cause of the decline in basking shark abundances from 1990 to 1997. This decline in sharks numbers and the northward migration of C. Helgolandicus coincided with a high NAO period. Climatic conditions were shown to have an overall effect on the basking sharks distribution in Cornish waters. A call of concern was address as to the overall effect global warming may have on the basking shark population